Implemented new VOEvent parameters and allowed preliminary VOEvents to include skymaps (although they aren't required to).

a plot of recent events on the landing page. The latter is
only shown if settings.SHOW_RECENT_EVENTS_ON_HOME is True.
Setting it to false for now, since we are not in a run.

Localize EMFootprint start times to UTC.
Changed event creation time query to assume UTC.

and added these to the event presentation. Also added frequency
and fluence to the VOEvent for LIB events.

to handle uploaded files with log entries submitted via
the web interface.

and email notifications. This is done by parsing
the label query separately and applying the filter
in a separate step.

send a x-throttle-wait-seconds header.